Electric motor for clothes washing machine drive

Abstract

An electric motor (2) for a clothes washing machine including the motor and a drive, the motor having a stator (25) held outboard of a frame carrying bearings (37, 38) in which a shaft (11) rotates, the shaft carrying the rotor (21) outboard of the stator (25), and permanent magnets (17) on an inner face of the rotor. The stator (25) is formed as an annular helical yoke edgewise wound from a strip of magnetic material and having an inner face and an outer face, the strip having pole pieces (8) formed integrally therewith extending from one edge of the strip and the strip being edgewise wound whereby the pole pieces coincide in stacked groups to form a plurality of poles arranged at equally spaced intervals extending radially outwardly from the outer face of the yoke. Energizable stator windings (26) are wound directly on the poles (8) of the stator and are adapted to be energized through an electronic commutation circuit (65,66) and the rotor (21) is mounted for rotation exteriorly of and relative to the stator, the rotor comprising a backing ring (16) of magnetic material and a series of permanent magnets (17) held at spaced-apart intervals on an inner surface of the backing ring (16) and opposing the poles (8) of the stator (25).

We claim: 
     
       1. An electric motor for a clothes washing machine comprising: a stator carrying energizable windings on poles thereof; a rotor; a motor frame having a single pair of spaced apart bearings mounted in said frame in a central disposition relative to said frame, said frame having stator locating means arranged to hold an outer cylindrical surface of said stator concentric with said bearings; and a single shaft rotatably mounted directly in said bearings and carrying said rotor, and at least one bearing of said pair of bearings being spaced at a remote position relative to said stator; wherein said rotor comprises a backing ring of a magnetic material, a series of permanent magnets spaced apart on an inner surface of said backing ring, said backing ring and magnets being rotatable exteriorly of said stator windings, a hub mounted on said shaft, and a backing ring support holding inner faces of said permanent magnets concentric with said shaft. 
     
     
       2. An electric motor as claimed in claim 1, wherein said stator is disposed outboard of said frame and with said rotor has a connecting portion between a hub and a rim and said connecting portion being outboard of said stator. 
     
     
       3. An electric motor as claimed in claim 1 wherein said stator comprises an annular helix of a magnetic material, said helix having said poles extending outwardly from the circumferential surface of an annulus, said annular helix being mounted on said stator locating means. 
     
     
       4. An electric motor as claimed in claim 1, wherein insulation to insulate said windings from said poles is provided and comprises a pair of moldings, each said molding being in the form of an annulus with insulation covering one part of each pole, there being a division intermediate of the thickness of each pole between the two moldings. 
     
     
       5. An electric motor for a clothes washing machine, comprising: a stator formed as an annular helical yoke edgewise wound from a strip of magnetic material and having an inner face and an outer face, said strip having pole pieces formed integrally therewith, the pole pieces extending from one edge of said strip and said strip being edgewise wound whereby said pole pieces coincide in stacked groups to form a plurality of poles arranged at equally spaced intervals extending radially outwardly from the outer face of the yoke; energizable stator windings wound directly on said pole pieces of said stator and adapted to be energized through an electronic commutation circuit; a rotor mounted for rotation exteriorly of and relative to said stator, said rotor comprising a backing ring of magnetic material and a series of permanent magnets held at spaced-apart intervals on an inner surface of said backing ring and opposing the pole pieces of said stator; a motor frame having a single pair of spaced-apart bearings mounted in said frame in a central disposition relative to said frame, said frame having stator locating means arranged to hold an outer cylindrical surface of said stator concentric with said bearings; and a single shaft rotatably mounted directly in said bearings and carrying said rotor, and at least one bearing of said pair of bearings being spaced at a remote position relative to said stator. 
     
     
       6. An electric motor as claimed in claim 5, wherein the inner face edge of said stator strip opposite the edge thereof from which said pole pieces extend is notched between each adjacent pole so as to reduce the width of said stator strip whereby adjacent poles are connected by a narrow band of strip material. 
     
     
       7. An electric motor as claimed in claim 5, and further comprising insulated moldings on said poles, said stator windings being wound on said insulated moldings. 
     
     
       8. An electric motor as claimed in claim 6, and further comprising insulated moldings on said poles, said stator windings being wound on said insulated moldings.